A blonde, blue-eyed and clean-cut child performer, Hart has been emerging from her teen years with great style and promise as a sitcom star. After making her debut as a four-year-old in a toy commercial, she appeared on such series as "The Lucie Arnaz Show", "The Equalizer", "Saturday Night Live" (in 1984) and in the TV longforms "Kane and Abel" (CBS, 1985) and "Christmas Snow" (NBC, 1986). In 1989, Hart temporarily abandoned TV and tried the New York stage, making her Broadway debut opposite Martin Sheen in a revival of Arthur Miller's "The Crucible" and off-Broadway in Circle Repertory Company productions of "Imagining Brad" and "Beside Herself".

But Hart moved back to the small screen when offered the starring role on the Nickelodeon teen-oriented series "Clarissa Explains It All" (1991-1994). Playing a smart, goofy, wise-mouthed kid, she became a teen idol and even after the series ended, continued to market popular "Clarissa"-related board games, books, videos and albums. Her new-found popularity resulted in guest spots on the shows "Where in the World Is Carmen Sandiego?", "Touched by an Angel", "Are You Afraid of the Dark?" and in the frenetic comedy "Family Reunion: A Relative Nightmare" (ABC, 1995).

"Clarissa" was no sooner wound up when Hart and her mother developed another successful, youth-oriented sitcom, spun off from the TV-movie "Sabrina, the Teenage Witch" (Showtime, 1996). The series (ABC, 1996-2000; The WB, 2000- ), which showcased Hart as a ditsy, perky high school student whose two zany aunts encourage her magical powers, has been favorably compared with the earlier "Bewitched" both in content and in its lighthearted, nonsensical spirit. Shortly before the "Sabrina" series debuted, Hart deviated from type with the TV-movie "Twisted Desire" (NBC, 1996), playing a teenage vamp who convinces her boyfriend to kill her parents. She provided the story for and starred in the NBC drama "Surviving Mary" (1997), about a college student investigating sex attacks on a college campus.